Request: Smart Access Memory information

[r1348]

Ryzen 3700X + ASRock X570 Pro4 + Sapphire Nitro+ RX580 SE

If I disable CSM and enable "Above 4GB decoding" in BIOS then I get:

r1348@localhost ~]$ AMD_DEBUG=info glxinfo | grep vram
vram_size = 8192 MB
vram_vis_size = 8192 MB
vram_type = 5
vram_bit_width = 256
has_dedicated_vram = 1

Too bad that, if I disable CSM, then I completely lose video output until OS takes over, skipping BIOS configuration and GRUB menu (system is dualboot). To restore I have to use the CMOS jumper reset, a good call to my late 90s sysadmin days.

It appears that this mobo and this video card UEFI don't interact well. I'd even upgrade my video card if the newer generations were, you know, there.

[agd5f]

yep.

[FONT=monospace][COLOR=#000000][ 0.998403] [drm] Detected VRAM RAM=8176M, BAR=8192M[/COLOR][/FONT]

gonna bother me til i learn what that's all about

It's reserved by the vbios for chip configuration data used by the driver.

[pete910]

5950x
VII GPU.
Asrock x570 Taichi

AMD_DEBUG=info glxinfo | grep vram
    vram_size = 16384 MB
    vram_vis_size = 16368 MB
    vram_type = 6
    vram_bit_width = 4096
    has_dedicated_vram = 1

To note it stated the same with my 3900x too on same board.

[doomie]

It's reserved by the vbios for chip configuration data used by the driver.

ah, thank you. for some reason vbios didn't occur to me, though it looked reserved by something indeed.

[Girolamo_Cavazzoni]

Ryzen 5 3500X
Asrock A520M-ITX (above 4G decoding enabled)
Radeon R9 Nano

vram_size = 4096 MB
vram_vis_size = 4096 MB
vram_type = 6
vram_bit_width = 512
has_dedicated_vram = 1

[bridgman]

I just want to caution everyone - don't turn on large BAR and forget about it, then be surprised if you have problems.

We are committing to test this on the latest HW only at this point - 570 chipset, Zen3 and 6800/6900/XT GPU. It's probably safe to assume that it will also work on whatever hardware Marek is using, but I wouldn't assume much more than that for now.

Feel free to see if your chipset supports large BAR, but recommend you turn it off after doing that unless you understand that you are working outside of what we test/fix and may run into problems.

[Nille_kungen]

Laptop with Ryzen 2500U

vram_size = 1024 MB
vram_vis_size = 1024 MB
vram_type = 8
vram_bit_width = 128
has_dedicated_vram = 0

[jaos]

Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: X570 AORUS ELITE WIFI
Version: F31o

Version: AMD Ryzen 9 3900X 12-Core Processor

Enabled >4G decoding and disabled CSM

[ 3.489289] [drm] Detected VRAM RAM=8176M, BAR=8192M

name of display: :0
name = NAVI10
marketing_name = AMD Radeon RX 5700 XT
vram_size = 8192 MB
vram_vis_size = 8176 MB
vram_type = 9
vram_bit_width = 256
has_dedicated_vram = 1

[user1]

If vram_vis_size is the same as vram_size, you have Smart Access Memory enabled. You both have it.

I have Ryzen 3900X but the chipset is only X370 and I can't find the option to enable SAM in the BIOS. I guess it depends on the motherboard vendor. (mine is Asus)

Did you look at System Agent (SA) Configuration under "advanced" section? That's how I found the "above 4g decoding" option which enables resizable BAR. I first thought it's under "boot" section.
Here is the output I get:

vram_size = 4096 MB
vram_vis_size = 4096 MB
vram_type = 5
vram_bit_width = 256
has_dedicated_vram = 1

Asus Prime Z390-P, Core i7 8700k, Radeon RX 580 4GB.

[pal666]

vram_size = 8192 MB
vram_vis_size = 8192 MB
vram_type = 5
vram_bit_width = 256
has_dedicated_vram = 1